Abstract The obesity epidemic is one of the foremost threats to the health of children and adults in the U.S today. Multidisciplinary pediatric weight management programs have been deemed effective, with increased access to these programs strongly advocated. However, the effectiveness of these programs is limited by attrition, with dropout ranging from 27-73%, limiting health benefits to children and inefficiently utilizing already scarce resources. Most research in this area is ad hoc, retrospective, observational, and inconsistent in the variables measured, leaving clinicians and researchers little in which to impact this phenomenon. In addition to better understanding the drivers of attrition, being able to predict or forecast dropout holds great potential to improve adherence and outcomes, and modify treatment approaches to best serve the needs of families. We have developed a model that isolates variables associated with attrition from pediatric weight management, with the potential to forecast participant dropout. We have the opportunity to expand and further refine this model through the collection of key data elements and increased study size. Therefore, we are proposing an expanded and refined approach to the study of attrition from pediatric weight management, utilizing the strength of increased participant numbers, acquisition of consistent data elements, and advanced analytic techniques. The overall goal of this project is to increase the accuracy and power of an attrition prediction model we have developed through its installation in additional weight management programs, then demonstrating its internal, external, and temporal validity. Finally, we will test this powerful tool as a means to decrease patient dropout. In Aim 1, we will increase the power and precision of the Outcomes Forecasting System (OFS) through the consistent acquisition of key patient, family, and treatment data, based on our conceptual model of adherence, from three different weight management sites. In Aim 2, external validity will be established through the installation of the OFS at a fourth pediatric weight management. Aim 3 will be an exploratory study of the feasibility and utility of the OFS in pediatric weight management programs to reduce attrition in high-risk patients and families. A greater understanding of patient, family, and disease-specific factors that predict dropout from pediatric weight management can be utilized to prevent attrition. Through the research aims proposed, the OFS will be refined to a level of precision, calibration, and efficiency to be a valuable tool to any weight management program. By identifying the most pertinent factors driving attrition across weight management sites, new avenues for treatment and prevention will be identified. This project will result in a valuable tool, available for dissemination across a diverse array of clinical programs to improve adherence, decrease costs, and improve outcomes.